org med

• Enzymes are catalysts produced as a result of cellular activity that occurs in abundance in plant and animal tissue.
• By general agreement most enzymes end in "ase,"
• Chemically they are proteins and are classified in six major categories
• Oxidoreductases, also known as dehydrogenases or oxidases, include alcohol dehydrogenases and glutamic dehydrogenases in the liver.
• Transferases, which catalyze the transfer of one-carbon groups, include aldehydes, ketones, phosphorus, and sulfur groups.
• Hydrolases catalyze hydrolysis of ester, ether, peptide, and other bonds, including such examples as pepsin and rennin
• Lyases catalyze removal of groups from substrates by means other than hydrolysis, leaving double bonds. They include ketone, aldehyde, and carbon-oxygen lyases.
• Isomerases, including enzymes, catalyze interconversion of optical and geometric isomers.
• Ligases catalyze the linking together of two compounds coupled to the breaking of a pyrophosphate bond. They include Succinate Co-A and Acetyl Co-A.
• how much the average healthy person makes daily - Three pints of saliva
• Three pints of saliva: that's how much the average healthy person makes daily. It's 99% water and 1% proteins, enzymes, and electrolytes.
• Saliva - It contains the enzyme amylase which breaks down select starches into maltose and dextrin, initiates fat breakdown, and starts digestion. It also contains role-specific proteins (eg, antibacterial histatins, protective statherins, lubricating mucins)
• Several hundred medications can cause or exacerbate xerostomia, including antihypertensives, antidepressants, analgesics, tranquilizers, diuretics, and antihistamines. These drugs affect the saliva's role in digestion
• Dry mouth, especially when it is chronic, drastically alters patients’ lives. They will find that the sore mucous membranes and gums, cracked lips and split corners of the mouth, and a rough, painful tongue make eating impossible. When teeth feel like razors, spicy foods set off alarms, and sleep eludes them because they wake to sip water, they need help.
• Lipases split fatty acids off fats and oils
• Proteases and peptidases split proteins into small peptides and amino acids.
• Amylases split carbohydrates such as starch and sugars into simple sugars such as glucose
• Nucleases split nucleic acids into nucleotides
• In the human digestive system, the main sites of digestion are the oral cavity, the stomach, and the small intestine.
• Digestive enzymes are secreted by different exocrine glands including:

  • Salivary glands

  • Gastric glands in the stomach

  • Secretory cells(islets) in the pancreas

  • Secretory glands in the small intestine
• Whilst for many clinicians, acid secretion is the most important aspect of gastric function that is studied in clinical practice, there are other facets that should be considered in drug development and measurements of gastric function.
• Pepsin is one of the major enzymes involved in gastric digestion and has a precursor called pepsinogen. Evidence for the existence of the two forms is based upon the difference in behavior of the two toward acids.
• Alkali destroys pepsin
• acids protect and aid it
• Alkali protects pepsinogen, whereas acids destroy it by converting it into pepsin.
• Physiologic function and Secreted product

  Killing or suppression of growth of ingested micro-organisms H+

  Facilitation of duodenal inorganic iron absorption H+

  Stimulation of secretin release - H+

  Suppression of antral gastrin release - H+

  Initiation of peptic hydrolysis of dietary proteins - H+, pepsin

  Liberation of vitamin B12 from dietary protein - H+, pepsin

  Binding of vitamin B12 for subsequent ileal uptake - Intrinsic factor

  Initiation of hydrolysis of dietary triglycerides - Gastric lipase

  Protection against noxious agents - Mucin, NaHCO3-, water, components of the mucus gel
• The function of the stomach includes initiation of digestion by exocrine secretions such as acid and Pepsin, which are under the control of the endocrine secretion of hormones that also coordinate intestinal motility.
• The stomach also stores and mechanically disrupts ingested food.
• Various techniques have been developed to assess gastric physiology, the most important of which is assessment of acid secretion, as well as gastric motility and gastric emptying.
• The influence of drugs on gastric function and the effect of gastric secretion and mechanical actions on the bioavailability of novel compounds are of critical importance in drug development and hence to clinical pharmacologists.
• The control of acid secretion is essential in the treatment of peptic ulcer disease as well as gastroesophageal reflux disease (GERD)
• pH-metry can be used to determine the necessary dose of an acid suppressant to heal mucosal damage.
• Disturbed gastric myoelectric activity leading to gastroparesis can cause delayed gastric emptying, often found in patients with diabetes mellitus.
• Electrogastrography (EGG) may be used to evaluate the influence of prokinetics and other drugs on this condition and aid in determining effective therapy.
• small intestine - is where most chemical digestion takes place.
• Most of the digestive enzymes in the small intestine are secreted by the pancreas and enter the small intestine via the pancreatic duct.
• three pancreatic enzymes

  • Pancreatic proteases
  • Pancreatic amylase
  • Pancreatic lipase
• Pancreatic proteases (such as trypsin and chymotrypsin) - digest proteins.
• Pancreatic amylase - which helps to digest sugars (carbohydrates)
• Pancreatic lipase - which Chemical Digestion in the Small Intestine helps to digest fat.